package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.text.DateFormat;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

// 全局唯一ID
@Component
public class RedisWorker {
    // 从2022年1月1日开始
    private static final long BEGIN_TIMESTAMP=1640995200L;
    
    private static final int COUNT_BITS=32;
    
    private StringRedisTemplate stringRedisTemplate;

    public RedisWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }
    
    public long nextId(String keyPrefix){
        LocalDateTime now = LocalDateTime.now();
        long nowSecond=now.toEpochSecond(ZoneOffset.UTC);
        // 当前和过去的时间戳
        long timeStamp=nowSecond-BEGIN_TIMESTAMP;
        
        String date=now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        
        long count=stringRedisTemplate.opsForValue().increment("icr:"+keyPrefix+":"+date);
        
        // |是或运算
        return timeStamp<<COUNT_BITS|count;
    }
}
